1. Field of the Invention
The present invention relates to a dispersion containing Cu ultrafine particles individually dispersed therein and more particularly to a dispersion containing individually dispersed Cu ultrafine particles, which can be used for forming fine distributing wires of semiconductor substrates such as LSI substrates and for embedding or filling up recessed portions, such as via holes and contact holes, formed on the substrates.
2. Prior Art
As metal pastes for forming a conductive, uniform and fine pattern used when forming multilayer distributing wires on semiconductor substrates such as LSI substrates, there have conventionally been known those comprising an organic solvent containing alcohols or organic esters which have not less than 5 carbon atoms and ultrafine metal particles having a particle size of not more than 1000 .ANG. (0.1 .mu.m) uniformly dispersed therein while the surface of the ultrafine particles are individually surrounded by or covered with the organic solvent (see, for instance, Gazetted Japanese Patent No. 2,561,537).
However, these metal pastes according to the conventional techniques suffer from the following drawbacks. As the width of the distributing wires formed on an LSI substrate has increasingly been finer from 0.25 .mu.m to 0.18 .mu.m or even more finer, the metal paste applied onto the substrate begins to be dried prior to sufficient embedding or filling up of grooves for distributing wires or it is difficult to completely embed or fill up fine grooves with the metal paste because the paste has a too high viscosity.